Companies use molding equipment to manufacture piston rings. For example, piston rings are manufactured through an injection molding process. As piston rings are cylindrical, they are formed in tapered cylindrical shaped molding equipment. In general, the known molding equipment for piston rings includes a mold cavity wall and a core. Pellets or granules of thermoplastic materials are heated to a molten state and forced into the space defined by the mold cavity wall. After the molten thermoplastic material has set or cured, there is a difficulty in removing the cured thermoplastic material from the cylindrical mold core as the material contracts upon the mold core causing an increased level of friction between the core and the generally tube-shaped or cylindrically shaped intermediate product to be ejected or separated. Consequently, the mold core of the molding equipment is limited in length and further includes a tapered or slanted surface to facilitate product ejection. However, the tapered surface of the mold core causes the intermediate product to have a tapered interior profile. The excess material caused by the tapered profile must be trimmed off to give a substantially constant diameter to the resultant piston ring. This waste material results in manufacturing inefficiencies.
In addition, the limited length of the intermediate product results in further manufacturing inefficiencies. This is because companies cut the intermediate product into slices to form the piston rings. Having shorter intermediate products increases the changeover time in moving from one intermediate product to another. Therefore, there is a need to overcome the disadvantages described above, or otherwise lessen the effects of such disadvantages.